Key takeaways:
Antibody-drug conjugates (ADCs) are a group of medications that treat many types of cancer, like breast cancer, blood cancers, and more.
ADCs are made up of three parts. They have a monoclonal antibody, a chemotherapy medication, and a protein that links them together.
ADCs target cancer cells more specifically than traditional chemotherapy medications. But they can still cause some serious side effects.
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Antibody-drug conjugates (ADCs) are a group of medications that treat cancer in a strategic way. They’ve been around for more than two decades, but they’ve gained more attention in recent years. The first ADC, Mylotarg (gemtuzumab ozagamicin), was FDA approved in 2000. More than 10 ADCs have since followed suit.
If you or a loved one have cancer, ADCs may cross your mind as a treatment option to discuss with your cancer specialist. A type of “smart” chemotherapy, ADCs have a more thoughtful approach than traditional chemotherapy. But they still have their own pros and cons to be aware of, so it’s important to know what to expect.
What are antibody-drug conjugates?
ADCs are different from traditional chemotherapy medications. Standard chemotherapy works by attacking fast growing cells in your body. But they’re not selective — they can affect cancer cells and healthy cells. This is what causes some of chemotherapy’s most common side effects.
ADCs bring together chemotherapy and targeted therapy into one treatment. ADCs are typically injected into your body as an infusion into your vein, and they’re made up of 3 parts:
A monoclonal antibody that targets cancer cells
A chemotherapy that kills cancer cells
A linker protein that holds the two together
How do ADCs work?
When you receive your infusion, the monoclonal antibody has the first job to do. It acts as a targeted therapy, so it aims to latch onto certain proteins that are common or unique to cancer cells — not healthy cells.
After the monoclonal antibody helps the ADC attach to cancer cells, the cancer cells absorb the medication. The linker protein holding everything together then breaks apart, and the chemotherapy is released inside the cancer cell. This kills cancer cells, which is ideal.
In other words, ADCs target cancer cells specifically and deliver chemotherapy inside them. This combination is like a Trojan horse for treating cancer.
Since the chemotherapy works inside cancer cells and not your bloodstream, this helps protect healthy cells from harm. In turn, this prevents some of the unpleasant side effects of chemotherapy. ADCs may also be useful in situations where other cancer treatments haven’t worked.
Are ADCs chemotherapy?
Yes. ADCs are a type of chemotherapy. Even though ADCs have other elements, they still contain a chemotherapy medication.
What are common examples of ADCs?
ADCs treat many types of cancer, like breast cancer, bladder cancer, and blood cancers. As of August 2022, twelve are FDA approved for use in the U.S.:
| Medication | Brand name | Approved uses |
|---|---|---|
| Gemtuzumab ozogamicin | Mylotarg | Acute myeloid leukemia |
| Brentuximab vedotin | Adcetris | Certain types of lymphoma |
| Inotuzumab ozogamicin | Besponsa | Acute lymphoblastic leukemia |
| Polatuzumab vedotin | Polivy | Diffuse large B-cell lymphoma |
| Ado-trastuzumab emtansine | Kadcyla | HER2+ breast cancer |
| Moxetumomab pasudotox | Lumoxiti | Hairy cell leukemia |
| Enfortumab vedotin | Padcev | Bladder cancer |
| Fam-trastuzumab deruxtecan | Enhertu | HER2+ breast cancer and stomach cancer |
| Sacituzumab govitecan | Trodelvy | Triple negative breast cancer Bladder cancer |
| Belantamab mafodotin | Blenrep | Multiple myeloma |
| Loncastuximab tesirine | Zynlonta | Large B-cell lymphoma |
| Tisotumab vedotin | Tivdak | Cervical cancer |
How effective are ADCs compared to other cancer medications?
It’s hard to say. Medication effectiveness is different for everyone — especially when it comes to cancer medications. Still, some ADCs were more effective than other medications in a couple studies.
For example, the EMILIA trial compared Kadcyla to the combination of Tykerb (lapatinib) and Xeloda (capecitabine) in people with advanced HER2+ breast cancer. In this study, people who received Kadcyla lived longer and had fewer side effects than people who were treated with Tykerb and Xeloda, the standard treatments at the time.
In another study, the ASCENT trial, people with metastatic triple negative breast cancer were given either Trodelvy or standard chemotherapy. In this study, people who received Trodelvy lived longer than those who received chemotherapy.
These are just a couple of examples where an ADC worked better than other cancer medications. It's important to keep in mind that not all ADCs have been studied this way. Many ADCs were approved based on studies that found them to be effective at treating cancer in a general sense. They weren’t compared to any other medication.
Can ADCs be combined with other cancer treatments?
It depends on the type of cancer being treated.
For example, it’s recommended to give Adcetris in combination with chemotherapy for certain people with Hodgkin lymphoma. This is also the case with Polivy. It can be given with chemotherapy and targeted therapy medications when treating non-Hodgkin lymphoma.
Other ADCs, like Kadcyla and Enhertu, are given by themselves after other cancer treatments haven’t worked. They aren't usually given with other chemotherapies at the same time.
To find out if an ADC may be used with other cancer treatments for your situation, speak with your cancer specialist.
What are the side effects of ADCs?
Although ADCs target cancer cells, they can still harm healthy cells by mistake. Sometimes, the chemotherapy part of an ADC leaks into the bloodstream before it reaches the cancer cells. This can lead to side effects, such as:
Lower blood cell counts, including red blood cells, white blood cells, and platelets
Increased liver enzymes
Hair loss
Stomach upset
Diarrhea
Shortness of breath
Some ADCs also cause their own unique side effects. For example, Blenrep can cause serious vision changes. It requires an eye exam before you start taking it. To learn more about specific side effects when starting an ADC, make sure to talk to your cancer specialist.
Will the FDA approve more ADCs in the future?
Yes, it's likely that more ADCs will be approved in the future. Many ADCs are currently being studied in clinical trials. In fact, ADCs are one of the fastest growing groups of medications being developed for cancer.
It's also possible that some already-approved ADCs will be approved for additional types of cancer. ADCs are here to stay, and they may play a larger role in treatment of cancer in the future.
The bottom line
ADCs are an expanding area of cancer treatment. Twelve ADCs have been approved in the U.S. so far, and it's likely that more will be approved in the future. They combine a targeted therapy and chemotherapy into one medication. To see if an ADC might be a treatment option for you or a loved one, it’s best to speak with your cancer specialist.
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References
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